If 30 fps is enough and human eye cant see the difference above that,then how come all YouTube videos dont look smooth at 30 fps ?
Because we are indeed able to " see" above 30 easily...
The human eye and its brain interface, the human
visual system, can process 10 to 12 separate images per second, perceiving them individually.
[1] The threshold of human visual perception varies depending on what is being measured. When looking at a lighted display, people begin to notice a brief interruption of darkness if it is about 16 milliseconds or longer.
[2] When given very short single-millisecond visual stimulus people report a duration of between 100 ms and 400 ms due to
persistence of vision in the
visual cortex. This may cause images perceived in this duration to appear as one stimulus, such as a 10 ms green flash of light immediately followed by a 10 ms red flash of light perceived as a single yellow flash of light.
[3] Persistence of vision may also create an illusion of continuity, allowing a sequence of still images to give the impression of motion. Early
silent filmshad a frame rate from 14 to 24 FPS which was enough for the sense of motion, but it was perceived as jerky motion. By using projectors with dual- and
triple-blade shutters, the rate was multiplied two or three times as seen by the audience.
Thomas Edison said that 46 frames per second was the minimum: "anything less will strain the eye."
[4][5] In the mid- to late 1920s, the frame rate for silent films increased to between 20 and 26 FPS.
[4]
When
sound film was introduced in 1926, variations in film speed were no longer tolerated as the human ear is more sensitive to changes in audio frequency. From 1927 to 1930, the rate of 24 FPS became standard for 35 mm sound film;
[1] the film travels through the projector at a rate of 456 millimetres (18.0 in) per second. This allowed for simple two-blade shutters to give a projected series of images at 48 per second.
Many modern 35 mm film projectors use three-blade shutters to give 72 images per second—each frame is flashed on screen three times.[4]
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Frame rates in video games refer to the speed at which the image is refreshed (typically in frames per second, or FPS). Many underlying processes, such as collision detection and network processing, run at different or inconsistent frequencies or in different physical components of a computer. FPS affect the experience in two ways: low FPS does not give the illusion of motion effectively and affects the user's capacity to interact with the game, while FPS that vary substantially from one second to the next depending on computational load produce uneven, "choppy" movement or animation. Many games lock their frame rate at lower but more sustainable levels to give consistently smooth motion.
The first 3D first-person game for a personal computer,
3D Monster Maze, had a frame rate of approximately 6 FPS, and was still a success. In modern action-oriented games where players must visually track animated objects and react quickly,
frame rates of between 30 and 60 FPS are considered acceptable by most, though this can vary significantly from game to game. Modern action games, including popular console games such as
Halo 3, are locked at 30 FPS maximum, while others, such as
Unreal Tournament 3, can run well in excess of 100 FPS on sufficient hardware. Additionally some games such as
Quake 3 Arena perform physics, AI, networking, and other calculations in sync with the rendered frame rate - this can result in inconsistencies with movement and network prediction code if players are unable to maintain the designed maximum frame rate of 125 FPS. The frame rate within games varies considerably depending upon what is currently happening at a given moment, or with the hardware configuration (especially in PC games).
When the computation of a frame consumes more time than is allowed between frames, the frame rate decreases.
A culture of competition has arisen among game enthusiasts with regard to frame rates, with players striving to obtain the highest FPS possible, due to their utility in demonstrating a system's power and efficiency. Indeed, many benchmarks (such as
3DMark) released by the marketing departments of hardware manufacturers and published in hardware reviews focus on the FPS measurement. LCD monitors of today are built with three major
refresh rate in mind. The most common is 60Hz, which can be used at any resolution without requiring high quality computer systems to render, and then 120Hz and 144Hz. The 120Hz standard also supports what is known as 'lightboost' technology in some monitors, where strobing lights behind the monitor reduce ghosting at high FPS rates.
Beyond measurement and bragging rights, such exercises do have practical bearing in some cases. A certain amount of discarded “headroom” frames are beneficial for the elimination of uneven (“choppy” or “jumpy”) output, and to prevent FPS from plummeting during the intense sequences when players need smooth feedback most.
Aside from frame rate, a separate but related factor unique to interactive applications such as gaming is
latency.
Excessive preprocessing can result in a noticeable delay between player commands and computer feedback, even when a full frame rate is maintained, often referred to as input lag.
Without realistic motion blurring, video games and computer animations do not look as fluid as film, even with a higher frame rate. When a fast moving object is present on two consecutive frames, a gap between the images on the two frames contributes to a noticeable separation of the object and its
afterimage in the eye. Motion blurring mitigates this effect, since it tends to reduce the image gap when the two frames are strung together. The effect of motion blurring is essentially superimposing multiple images of the fast-moving object on a single frame.
Motion blurring makes the motion more fluid for some people, even as the image of the object becomes blurry on each individual frame. Motion blur can also induce headaches when people play a game that requires concentration.[16]
A high frame rate still does not guarantee fluid movements, especially on hardware with more than one GPU. This effect is known as micro stuttering.
Source: Wikipedia
So this subject cant have a "perfect" fps definition or a fixed fps for everything from movies to games.
Its possible for some people to see the difference from 50 to 60 or even 70 and slightly above,and for others to see no change above 30 or 40 and so on.
This depends on what monitors we have,PC hardware and games or videos themself.
Any change in this area will give different end results for different people.
For me,yes i can "see" the difference from 40 to 50 and even 50 to 60 (slightly) but above that,from 60 above i notice no change in my view.70,80,90,100..nothing.
The only thing that changes as the fps go up is the "Visual imput lag" of the ingame steering wheel (Assetto Corsa) where above 80 fps even that "visual imput lag" for the steering wheel is gone.
After this step all the extra fps you can get is for confort of having no issue when we run full AI races or online multiplayer because of fps "eaters".
